Thioformamide compounds



Patented Dec. 9, 1941 THIOFOWE COMPOUNDS Kurt Westphal and Hans Andersag, Germany, assisnors Company. New

Elliot! to win York, N. 1., a

corporation or New York No Drawing.

' This invention relates to a process of manufacturlng thioformamides.

Thioformamide compounds have been hitherto prepared by various methods. According to one of the most usual methods thioformamide compounds are obtained by heating formamide compoundswith phosphorus pentasulflde. This method, however, is not useful in every case, for instance cannot be used if the formamide compound which is to be reacted with phosphorus pentasulflde simultaneously contains further groups which likewise react with phosphorus pentasulflde or which are not suiiiciently stable when treated with phosphorus pentasulflde.

The present invention provides for a process by which thioformamide compounds are ob tained in a particularly favorable manner. In accordance with the present invention thioformamide compounds, substituted at the nitrogen atom by an organic radical, are obtained by reacting upon an amine containing at least one hydrogen atom in the amino group'with thioformamide. It is surprising that the reaction which takes place with splitting oil of ammonia performs in general even at ordinary temperature. Hence the new reaction has the advantage when compared with the known reactions that practically no by-reactions occur. The reaction preferably is carried out in the presence of a solvent or diluent which is inert to the reacting components, such as water, alcohols, ether, dioxane and the like. The reaction may also be performed in such a manner that the thicformamide is caused to form from formamide and phosphorus pentasulflde in the presence of the respective amine and, if desired, of an inert solvent and with the addition of an acid binding agent. The most various primary and secondary organic amines, particularly also polyamines, of the aliphatic, cycloaliphatic, aromatic, araliphatic and heterocyclic series, may be used for the above described reaction. The amino group itself may be present in heterocyclic linkage,

as for instance in pyrrolidine and piperidina.

The reaction is most satisfactory with the strongly basic amines, containing an aliphatically bound amino group, such as methyland dimethyl-amine, ethyland diethyl-amine, ethylenediamine, aminoethanol, propylhydroxypropyl-amine, butylamine, pentylamines, cyclopentylamine, hexylamines, cyclohexylamine, octylamine, benzylamine, amino methyl-pyridines, aminomethyl-pyrimidines and so on. Suitable aromatic and heterocyclic IlMay 9, 1939, Serial Applioatio In Germanyliay 12, 1988 10 (Balms. (01. 260-251) amines are for instance aniline, toluidine, ylenediamine, naphtylamine, a-amino-pyrldine and aminoquinolines. Theaminesmaybouled grtsthe reaction as such or in the form of their The thioformamide compounds thus obtainable are in part used as initial materials for chemical syntheses or may be in part used as such for technical purposes.

The invention is illustrated by the following examples without being restricted thereto:

- Example 1 6 grams of formamide, 6 grams of phosphorus pentasulflde and cos. of dioxane are vigorously stirred for 12 hours. The dioxanesolution is poured off and the solvent is removed therefrom under reduced pressure at 40 C. The residue containing the thioi'ormamide formed is dissolved in 30 cos. of water, the solution is filtered and mixed with a solution of 8.5 grams of piperidine in 20 cos. of water. After 12 hours storing the solution is acidified with hydrochloric acid and extracted with methylene chloride. After drying by way of sodium sulfate and removing of the solvent the N-thioformyl piperidine formed distils as a yellow oil under 14v mms1d pressure at 0., which solidifies in the co The same compound can be obtained when mixing 6.1 grams of thioformamide and 8.5 grams of piperidine without a solvent while thoroughly cooling. After 12 hours storing the solution is acidified with hydrochloric acid. The insoluble oil is extracted with ether, the ethereal solution dried, freed from ether and the residue is fractionated. The N-thioformyl-pyrrolidine boiling under 9 mm. pressure at 132 to 134 C. is obtained in an analogous manner.

Emmple 2 A solution of 12.7 gra1ms of thioformamide obtained as described in Example 1 in 100 cos. of

alcohol is mixed with a solution of 15 grams of diethylamine in 50 cos. of water. After some hours theyellow solution is evaporated to dryness under reduced pressure. The residue is extracted with ether, the ethereal solution dried with and 50 sodium sulfate and the ether distilled off. The

residue boils under 15 ms. pressure at 112-413 C. The N-diethyl-thioform'amide is obtained as a yellow oil.

The diethyl-thioformamide can also be obtained when performing the reaction, as depheni scribed in Example 1, paragraph 2, without a solvent.

In an analogous manner the following products are obtained:

N,N-dithioformyl-ethylenediamine melting at 147 C., N-thioformylamidoethanol boiling under 1.5 mms. pressure at 135 C., N-thioformyldimethylamine boiling under 12 mms. pressure at 97 C., N-thioformyl-ethylamine boiling under 14 mms. pressure at 125 C., the N-isoamylthioformamide boiling under 8 mms. pressure at 140 C., the N-thioformyl-benzylamine melting at 65 C. and the N-thioformyl-isohexylamine boiling under 2 mms. pressure at 125 C.

. Example 3 A mixture of 11.3 grams of phosphorus'pentasulfide, 250 ccs. of anhydrous ether and 11.3 grams of formamide'is shaken for 12 hours. Thereupon the ethereal solution is poured off and freed from ether under reduced pressure at room temperature. The residue is dissolved in 100 ccs. of alcohol, filtered and mixed with a solution of 26 grams of 2-methyl-4-amino-5-aminomethyl-pyrimidine in 150 cos. of alcohol. After a short time crystallization begins with a slight increase of temperature. After some hours the solution is filtered with suction and the crystals recrystallized from dilute alcohol. The 2-methyl- 4-amino-5-thioformamido-methyl-pyrimidine is obtained in white crystals melting at 193 C.

The same substance is obtainable when dissolving the components in water or in dilute dioxane instead of alcohol and mixing the solutions.

The same product can be obtained when using instead of 26 grams of 2-methyl-4-amino-5- aminomethyl-pyrimidine in 150 ccsfof alcohol a solution of 32 grams of its carbonate in 200 cos. of water. 7

Example 4 An alcoholic solution of thioformamide. prepared according to Example 1 from 2.26 grams of formamide, 50 ccs. of dioxane and 2.26 grams of phosphorus pentasulfide, is mixed with a'solution of 3.5 grams of aniline in 40 ccs. of alcohol. After a 12 hours storing the solution is evaporated to dryness under reduced pressure and extracted with dilute hydrochloric acid. The insoluble residue is extracted with dilute aqueous sodium hydroxide solution and the alkaline solution is acidified with acetic acid. The crystals precipitated are filtered with suction and recrystallized from water. The N-thioformylaniline is obtained in white crystals melting at In an analogous manner the N, N'-dithioformyl-meta-phenylenediamine melting at 147' C. is obtained.

Example 5 A crude thioformamlde preparation obtained according to Example 4 is dissolved in 20 ccs. of chloroform and mixed with a solution of 5.4 grams of fi-amlnoquinoline in chloroform. After 12 hours the solution of chloroform is shaken out with dilute aqueous sodium hydroxide solution and the latter is slightly acidified with acetic acid. The crystals precipitated are filtered with suction and recrystallised from acetone. White crystals of the G-thioformylamido-quinoline are obtained, melting at 238 C.

We claim: I

1. The process of manufacturing thioformamide compounds by reacting upon a halogenfree amine containing at least one hydrogen atom in the amino-group with thioformamide.

'2. The process of manufacturing thioformmidecompounds by reacting upon a halogen-free amine the amino group of which is aliphatically bound and contains at least one hydrogen atom, with thioformamide.

3. The process of manufacturing thioformamide compounds by reacting upon a halogenfree primary amine, the amino group of which is aliphatically bound, with thioformamide.

4. The process of manufacturing thioformamide compounds by reacting upon a 5-aminomethyl-pyrimidin with thioformamide.

5. The process of manufacturing thioformamide compounds by reacting upon Z-methyl- 4-amino-5-aminomethyl-pyrimidine with thioformamide.

6. Process as claimed in claim 1 in which the reaction is carried out in the presence of a diluent which is inert to the reacting components.

7. Process as claimed in claim reaction is carried out in the diluent which is inert to the ponents.

8. Process as claimed in claim reaction is carried out in the diluent which is inert to the ponents.

9. Process as claimed in claim 4 in which the the reaction is carried out in the presence of a diluent which is inert to the reacting components.

10. Process as claimed in claim 5 in which the reaction is carried out in the presence of a diluent which is inert to the reacting components.-

2 in which the presence of a reacting com- 3 in which the presence of a reacting com- KURT WESTPHAL. HANS ANDERSAG. 

